Froth flotation method for recovery of minerals

ABSTRACT

An improved method in concentration of oxidic ores by froth flotation process which comprises subjecting an oxidic ore or mineral of a metal which can change the valency state from higher to lower by the action of inorganic reducing compounds in the presence of an effective quantity of a flotation collectorfrother propiolic acid adduct of polyhydric alcohol or propargyl carbinol or polyhydroxycarboxylic acid, the indicated compounds provide selectivity and/or recovery of oxide minerals of manganese, tin, titanium, samarium, and ytterbium, over silica and silicate gangue.

Petrovich [4 1 Sept. 2, 1975 FROTH FLOTATION METHOD FOR RECOVERY OF MINERALS Vojislav Petrovich, 1925 W. Schiller St., Chicago, 111. 60622 22 Filed: Nov. 6, 1973 21 Appl. No.: 409,774

Related US. Application Data [63] Continuation-impart of Ser. No. 251,458, May 8,

1972, abandoned.

[76] Inventor:

[52] US. Cl. 209/166 [51] Int. Cl. B03D 1/02 [58] Field of Search 209/166, 167

[56] References Cited UNITED STATES PATENTS 1,670,021 5/1928 Clark 209/166 1,706,293 3/1929 Holladay. 209/166 1,774,786 9/1930 Callow 209/166 1,788,331 1/1931 Schafer 209/167 1 2,023,388 12/1935 Harris 209/166 X 2,120,217 6/1938 Harris 209/166 2,122,659 7/1938 Ra1ston...... 209/166 2,312,466 3/1943 Erickson 209/166 2,393,008 1/1946 Woodward... 209/166 2,952,532 9/1960 Cox 209/166 X 3,339,730 9/1967 Boutln 209/166 Primary Examiner-Robert Halper [5 7] ABSTRACT v An improved method in concentration of oxidic ores by froth flotation process which comprises subjecting an oxidic ore or mineral of a metal which can change the valency state from higher to lower by the action of inorganic reducing compounds in the presence of an effective quantity of a flotation collector-frother propiolic acid adduct of polyhydric alcohol or propargyl carbinol or polyhydroxycarboxylic acid, the indicated compounds provide selectivity and/or recovery of oxide minerals of manganese, tin, titanium, Samarium, and ytterbium, over silica and silicate gangue.

4 Claims, N0 Drawings F ROTH lFLOTATION METHOD FOR RECOVERY OF MINERALS This is a continuationin-part of my prior application of No. 251,458 filed on May 8, 1972, now abandon. in favour of the present application.

RELATED APPLICATIONS The prior art discloses the application of reducing agents in conjunction with various flotation oils. German Pat. No. 779,467 teaches the use of hyposulfites as depressor for zinc minerals, but as activator for arsenical ores. US. Pat. No. 1,670,021, discloses the use of acetylene gas in conjunction with glucose as reducing agent, and aniline, linseed oil and pine pine oil as collector and frother.

BRIEF SUMMARY OF THE INVENTION This invention relates to the concentration of metal values from minerals and ores. Particularly, it relates to the use of propiolic acid adducts of polyhydric alcohols and polyoxymethylene as flotation agents with collecting and frothing properties to effect a separation of metal values in ores from silica, alkali and earth alkali aluminum silicates. The minerals and ores of which the metal values are to be floated out are pretreated with reducing agents which presumably change the metal valency state at the mineral surface of respective metal. The lower valency state of the respective metal presumably activates the triple bond of acetylenic collector-frother, thus effecting a successful flotation of the desired metal values from the mineral slurry. Among such ores and minerals, to the beneficiatingof which this invention is particularly adapted, are the oxide ores of manganese, tin, titanium, Samarium, and ytterbium, i.e., and particularly the dioxide of manganese as is psylomelan and pyrolusite, cassiterite mineral of tin, rutile and ilmenite minerals of titanium.

Another object of the present invention is a beneficiation process effective economically to recover the heretofore said metallic values from silica and silicate gangue.

One or more of the foregoing objects is achieved by the present invention.

The present invention comprises a process for the beneficiation of minerals and ores of metals which can change the valency state, so that the metal at the mineral surface is presumably reduced to a lower valency state, in which state is presumably acts as a catalyst on the triple carbon to carbon bond of the acetylenic collector-frother, which as a double vr-bond compound, presumably attaches the acetylenic collector-frother to the mineral surface. Thus the process comprises comminuting the ore to substantially complete liberation of the valuable mineral from the gangue, pretreating the ore slurry with a inorganic reducing agent to modify at least a portion of the surface of the mineral which is to be floated by forming some lower metal oxide, and sub jecting the comminuted surface modified ore or mineral to the beneficiation by froth flotation method in the presence of propiolic acid adduct of polyhydric alcohols as are glycerol, diglycerol, hexantriol, polyoxymethylene.

More particularly described, the present invention comprises contacting comminuted ore or mineral of the above said metals with inorganic reducing agents believed to effect a change in the surface oxidationreduction potential of the ore particles, which particles believed to exert by its acquired oxidationreduction potential a change in the oxidation-reduction potential of the triple carbon to carbon bond of acetylenic compounds which serve in this invention as collecting agents.

While it is not desired to be bound by the theory here exposed, some light must be thrown on the supposed process, for the comminuted ore according to the process of the invention results either in actual chemical reduction of portion of the surface of the mineral of the metal which normally and naturally form lower valency states, or alternatively, alters the oxidation-reduction potential of portion of the surface of the metalliferous particles. The foregoing discussion shows that the oxidation state concept can be used to determine whether a given chemical reaction involves oxidation-reduction and further, to help in balancing the equations for such processes where balancing by inspection fails.

In discussing oxidation-reduction reactions the species that is reduced is called the oxidizing agent or oxidam, and the species that is oxidized is called the reducing agent or reductant. Where simple ions are involved, the oxidizing agent is the electron donor; or respectively the reducing agent is the electron acceptor; thus the oxidation state changes can be used to identify the oxidizing and reducing agents. In the respective cases, the flotation of a mineral, the mineral particles in the aqueous pulp of the mineral slurry may presumably exert the quality of oxidizing or reducing agent in contact with ionic oxidizing or reducing agents, thus oxidized or reduced they may exert oxidizing or reducing properties on the species which can change the valency state, i.e., to be oxidized or reduced, or anyhow change the oxidation-reduction potential. This theoretic assumption, which was proved in numerous froth flotation tests, is the essence of this invention. Thus the mineral particle may be donor or acceptor of electron in contact with a reducing or oxidizing agent.

The reduction corresponds to a decrease in oxidation state in the positive sense; oxidation correspond to an increase in oxidation state in the positive sense. The conventional algebraic sum of the changes in oxidation states in the balanced equation for an oxidationreduction reaction is zero.

In general, when ionic compounds are formed from their elements, electron transfer is complete, and oxidation and reduction in the modern sense can be readily discerned; but when covalent molecules result, what presumably occurs in oxidation or reduction of mineral surface in flotation in which reaction only a partial transfer of electrons from one element to the other occurs, the oxidation-reduction nature of the process is obscure. Oxidation-reduction reactions of the latter type are conveniently described using the concept of the oxidation state of an element. Oxidation state is a convention based on a set of rules, and has the advantage of applicability to oxidationreduction reaction regardless of whether a complete or partial transfer of electrons is involved. Furthermore, chemical reactions involve changes in the distribution of the electrons about the nuclei of the reacting particles, whether they be atoms, molecules, or ions. Some of the changes involve a more or less complete transfer of electrons from one of the reacting particles to another. And because an oxidation is always accompanied by reduction so that electrons are neither created nor destroyed in the transfer, it may be supposed that the carbon to carbon triple bond is reduced by supposedly lower oxide, i.e., lower =-;ldizing state of the respective metal at the mineral sur; aze, so that the carbon to carbon triple bond acts as oxidizing agent, becauseof which the new state of things find its solution in a presumably new compound of metal hydrocarbon compound. On this basis the process is operative which was proved, for the metals of the ores treated in accordance with the invention are rendered responsive to froth flotation process.

The present invention embraces inorganic reducing agents with a high positive oxidation-reduction potential. Suitable agents for the practising of the present invention include: hypophosphorous acid, hypophosphites, phosphorous acid, phosphites and phosphorus trichloride, hyposulfurous acid and hyposulfites, sulfurous acid and sulfites.

The amount of the reducing agent employed in the practising of the present invention may vary depending upon the nature of the ore, the conditioning time and the like operations. The reducing agents of this invention are preferably employed in amounts ranging from 0,05 pound per ton to about 0,3 pound per ton of ore treated.

The consumption of acid and alkali which are employed as auxiliary reagents to'bring the pH values to the necessary concentration to fulfill the reduction in an acidic or alkaline media is low and never more than two pounds per ton of ore milled; approximately one pound per ton is sufficient, so that the pH of the pulp of the mineral slurry is operative between 5 and 9, which depends on the electronegativity of the metal in the mineral to be floated, i.e., of the oxidationreduction potential involved in the process. The time of contact of the reducing agent and the ore may be varied between wide limits depending on the particular ore treated as well as the concentration of the reducing agent.

The collector-frothers employed in this froth flotation process of my invention are propiolic acid adducts of polyhydric alcohols with no more than six hydroxyl groups per molecule, i.e., glycerol, diglycerol, hexanetriol, polyoxymethylene; as well as propargyl carbinol adducts of polyhydroxycarboxylic acids with no more than six hydroxyl groups per molecule, i.e., glycerolglyceric acid, gluconic acid, saccharic acid.

Collector-frothers of the present invention which presumably function by the chemical reaction based on the activation of the triple carbon to carbon bond of an acetylenic compound, i.e., the rr-bond, by the action of a metal in a lower oxidation state formed at a portion of the surface of the mineral to be floated, forming with the metal atoms exposed on the surface of mineral particle presumably addition compounds, make that the process is operative.

The lower oxidizing state of a metal at the mineral surface, provoked by a strong inorganic reducing agent, is eager of bonding, i.e., of reducing. If for instance potassium permanganate is added, the lower oxidizing state, i.e., the lower metal oxide will oxidize to higher, i.e., to the higher valency state in the respective case of metal dioxide, psilomelan, cassiterite, or titanium dioxide, as they were before the treatment with inorganic reducing agent. But with a collector-frother with triple carbon to carbon bond no oxygen as electron carrier is introduced in the electron transfer reaction, but a potentially high valency state, so to speak,

with ready disposable valency eager of bonding. Such an active state in a pulp of mineral slurry forces a new state of things resulting in compounding the disposable lower metal valency state of a lower oxide and hydrocarbon with frothing properties. The triple carbon to carbon bond of the collector-frother is lost, because the disposable bond binds directly to metal forming a kind of metal-organic compound. Thus, an acetylenic compound acts as an oxidizing agent by suturation of metal binding deficit to optimum valency by stretching the disposable rr-bond, forming thus metal-organic compound. ln such a kind of electron transfer reaction acetylenic compound of collector-frother of this invention becomes a saturated hydrocarbon, which having the frothing properties effect the flotation of said minerals from their ores. The compound with triple carbon to carbon bond having an oxidation-reduction potential of O,73 volt, acts as oxidizing agent being reduced to double or single carbon to carbon bond, losing at the same time its electromotive force. Thus, oxidationreduction reaction in modern meaning has no more exclusive connection with augmenting or lowering of oxygen in oxidation-reduction reactions, for acetylenic compounds as is in the respective case of this invention are electron acceptors, therefore acting as oxidizing agents.

It is obvious that the rest of the hydrocarbon compound or substituted hydrocarbon compound is oriented outward from the said particle. Thus the attachment of these (nonionic) collector-frothers to the ore particles form a water repellent surface or a barrier around at least a part of the surface of the ore particle and thereby facilitate the formation of froth when the ore slurry is agitated in the presence of air.

In view of the above outlined necessary characteristics of a good collector-frother, it would appear that it is necessary, for the acetylenic compound of applicants collector-frother, to be of a particular size, i.e., have an upper and a lower size limit or chain length. It has been found that the acetylenic compound should contain about 8 carbon atoms or more and two to six hydroxyl groups in the adduct side chain attached to about 6 carbon atoms or more.

The upper limit on the size or number of carbons in the acetylene carboxylic acid is determined primarily by the factors which necessitate to attach the metal in the mineral to be floated, i.e., the strength and scope of the bonding so to speak, and not to the solubility factor. The acetylene portion of the molecule should have from 8 to 14 carbon atoms. The upper limit of the adduct is about 22 carbon atoms in which a maximum of six hydroxyl groups are attached to six carbon atoms. Hence, the preferred acetylene carboxylic acid adducts of polyhydric alcohols contain 14 to 22 carbon atoms respectively, or the preferred acetylene carbinol adducts of polyhydroxycarboxylic acids contain 14 to 22 carbon atoms.

The preferred embodiments of collector-frothers are as follows:

A mylpropiolic acid adduct of glycerol Hexylpropiolic acid adduct of diglycerol Hexylpropiolic acid adduct of hexantriol Heptylpropiolic acid adduct of polyoxymethylene Dodecylpropiolic acid adduct of polyoxymethylene Propargyl carbinol adduct of glycerolglyceric acid Propargyl carbinol adduct of saccharicpolyethylene glycol ester Amylacetylene carbinol adduct of glycerolglyceric acid Heptylacetylene carbinol adduct of gluconic acid Undecylacetylene carbinol adduct of saccharic acid.

The method of making the various adducts is well known and described in the literature. Therefore, their method of preparation does not constitute apart of the invention.

In the use of collector-frothers, based on the 7T-b0l'ld activity, to float the mineral values, the ore is crushed, milled and sized to at least about 60 to 100 mesh, which depends on the particular ore treated; Milling to finer sizes is preferable The crushed and sized ore is pulped and as a mineral slurry is ready for treatment in the flotation equipment with the reducing agent, which is always accomplished prior to the addition of acetylenic collector-frother. After reducing of the mineral surface is accomplished the collector-frother and auxiliary agents, if any are to be used, are added for further treatment in the flotation equipment. In the flotation cell the ore pulp is contacted with air to form a froth to achieve the desired separation of metal values from the gangue. Normally, the metal values are present in the froth, overflow from each cell or stage. In most cases it is advantageous to use a multiple stage flotation process to treat the underflow or partially metal values barren pulp to increase the degree of separation or to enhance the degree of recovery. Also, the use of varying amounts of emulsifiers, dispersants and depressants etc. in different stages may be used to advantage to obtain the highest yield and best separations. The used water of the flotation circuit may be recycled, as well as the used water of conditioning-milling circuit, which is an advantage economically as well as for the environment protection from the water polution.

Having disclosed the novel collector-frother of this invention as well as the handling of the ore wherein the use of activation steps as is the reducing of a portion of the mineral surface, the last object of this invention is to provide a method for the flotation recovery of minerals containing oxides of manganese, tin, titanium, samarium and ytterbium.

The above discussion illustrates my invention in a general way, but for a detailed illustration thereof the examples of flotation procedure are set forth below.

Hexylpropiolic acid adduct of hexantriol.

The activator-promoter used: The collector-frother used:

500 grams of a lode psylomelan containing 19,3 percent manganese metal, was ground wet at 67 percent solids'in a laboratory ball mill to pass 100 mesh sieve. In the flotation machine 0,3 pound per ton of potassium hyposulfite was added for reducing the psylomelan surface. Conditioned for five minutes, then added 0,3 pound per ton of hexylpropiolic acid adduct of hexantriol. conditioned for five minutes, then aerated. The rougher concentrate was skimmed for 5 minutes, and cleaned with used water and 0,05 pound per ton of collector-frother.

The results of this test were as follows:

Weight Assay Distribution Product percent percent of manganese Mn percent Concentrate 33,7 55,1 96,2 Tail, general cleaner 66,3 .l,l2 3,8

EXAMPLE 2 The activator-promoter used: The collector-frother used:

500 grams of a lode cassiterite containing 4,1 percent of tin metal, was ground wet a 67 percent solids in a laboratory ball mill to pass 65 mesh sieve. In the flotation machine 0,1 pound per ton of potassium hypophosphite was added for reducing the cassiterite surface. Conditioned for three minutes, then added 0,1 pound per ton of hexylpropiollic acid adduct of diglycerol. Conditioned for three minutes, then aerated. The rougher concentrate was skimmed for four minutes, the rougher concentrate was cleaned with used water and 0,05 pound per ton of collector-frother.

The results of this test were as follows:

Weight Assay Distribution Product percent Sn of tin percent percent Concentrate 7,5 52,4 94,5 Tail, general cleaner 92,5 0,22 5,5

EXAMPLE 3 The activator-promoter used: The collector-frother used:

Potassium phosphite. Hepuylpropiolic acid adduct of polyoxymethylene.

Weight Assay Distribution Product TiO of TiO percent percent percent Concentrate 25,2 29,0 90,6 Tail, general cleaner 74,8. [,0 9,4

It is understood that the heretofore detailed discussion is for the purpose of illustration only, and is not intended as being limiting to the spirit of the invention or scope of the appended claims.

I claim:

1. An improved method of beneficiating ores and minerals selected from the group of oxide ores of manganese, tin, titanium, samarium, ytterbium, by froth flotation process to produce a froth concentrate of desired metal value which improvement comprises, effecting the froth flotation of the ore by treating the comminuted ore of the mineral slurry with inorganic reducing agents to reduce the surface of the oxide to be floated, followed by an effective amount of a collectorfrother of propiolic acid adduct of polyhydric alcohols said alcohols having two to six hydroxyl groups per molecule, or propargyl carbinol adduct of polyhydroxycarboxylic acids said acids having two to six hydroxyl groups said adducts having from 14 to 22 carbon atoms; and recovering a froth concentrate relatively rich in the desired metal value to leave the tailings relatively poor in the desired metal value. I

2. A method according to claim 1, wherein the inorganic reducing agent are selected from the group of inorganic reducing acids or their salts consisting of hypophosphorous acid and hypophosphites, phosphorous acid and phosphites, phosphorus trichloride, hyposulfurous acid and hyposulfites, sulfurous acid and sulfites.

3. A method according to claim 1-, wherein the collector-frother is propiolic acid adduct of glycerol, diglycerol, hexanetriol, polyoxymethylene, or mixture thereof, said adducts have from 14 to 22 carbon atoms, said propiolic acids have from 3 to 12 carbon atoms.

4. A method according ro claim 1, wherein the collector-frother is propargyl carbinol adduct of glycerolglyce ric acid, gluconic acid, saccharic acid, or mixtures thereof, said propargyl carbinols have from 4 to 12 carbon atoms, said adducts have from 14 to 22 carbon atoms. 

1. AN IMPROVED METHOD OF BENEFICIATING ORES AND MINERALS SELECTED FROM THE GROUP OF OXIDE ORES OF MANGANESE, TIN, TITANIUM, SAMARIUM, YTTERBIUM, BY FROTH FLOTATION PROCESS TO PRODUCE A FROTH CONCENTRATE OF DESIRED METAL VALUE WHICH IMPROVEMENT COMPRISES: EFFECTING THE FROTH FLOTATION OF THE ORE BY TREATING THE COMMUNITED ORE OF THE MINERAL SLURRY WITH INORGANIC REDUCING AGENTS TO REDUCE THE SURFACE OF THE OXIDE TO BE FLOATED, FOLLOWED BY AN EFFECTIVE AMOUNT OF A COLLECTORFROTHER OF PROPIOLIC ACID ADDUCT OF POLYHYDRIC ALCOHOLS SAID ALCOHOLS HAVING TWO TO SIX HYDROXYL GROUPS PER MOLECULE, OR PROPARGYL CARBINOL ADDUCT OF POLYHYDROXYCARBOXYLIC ACIDS SAID ACIDS HAVING TWO TO SIX HYDROXYL GROUPS SAID ADDUCTS HAVING FROM 14 TO 22 CARBON ATOMS, AND RECOVERING A FROTH CONCENTRATE RELATIVELY RICH IN THE DESIRED METAL VALUE TO LEAVE THE TAILINGS RELATIVELY POOR IN THE DESIRED METAL VALUE
 2. A method according to claim 1, wherein the inorganic reducing agent are selected from the group of inorganic reducing acids or their salts consisting of hypophosphorous acid and hypophosphites, phosphorous acid and phosphites, phosphorus trichloride, hyposulfurous acid and hyposulfites, sulfurous acid and sulfites.
 3. A method according to claim 1, wherein the collector-frother is propiolic acid adduct of glycerol, diglycerol, hexanetriol, polyoxymethylene, or mixture thereof, said adducts have from 14 to 22 carbon atoms, said propiolic acids have from 3 to 12 carbon atoms.
 4. A method according ro claim 1, wherein the collector-frother is propargyl carbinol adduct of glycerolglyceric acid, gluconic acid, saccharic acid, or mixtures thereof, said propargyl carbinols have from 4 to 12 carbon atoms, said adducts have from 14 to 22 carbon atoms. 